Euclidean-invariant Klein-Gordon, Dirac and massive Chem-Simons field
theories are constructed in terms of a random walk with a spin factor
on a three-dimensional lattice. We exactly calculate the free energy a
nd the correlation functions which allow us to obtain the critical dif
fusion constant and associated critical exponents. It is pointed out t
hat these critical exponents do not satisfy the hyper-scaling relation
but the scaling inequalities. We take the continuum limit of this the
ory on the basis of these analyses. We check the universality of the o
btained results on other lattice structures such as the triclinic latt
ice and the body-centered lattice.